Word of caution - you have to be precise with installing the lock so that when the door closes, the electronic lock mechanism can lock the door with no friction. 

Moreover, I am interested in knowing what more experienced investors would consider essential or important components to include, which might not be obvious to me after reading chapter 4 (Investment business plan section) of the beginners guide posted here on B.P My primary long term interest is buy and hold 10 - 50 unit B or C+ properties in steady growth markets with an emphasis on cash flow.

That said, I personally can fix almost anything mechanical.

These older homes come with a lot of baggage, most contractors will not point out the mechanics and go straight to paint and laying flooring. 

As far as the restaurant space goes if you have equipment in the space you want to make sure the tenant performs regular maintenance on all of the equipment mechanical systems etc.  

For my mechanicals (furnace, a/c, water heater etc) I have a plumber come do a clean/service when I first buy a place.

-You already live here and have spent the money, so I wouldn't put as much emphasis on your purchase cap rate.

But, I don't rebuild my own transmissions despite my incredible mechanical aptitude, and I don't cut my own hair, or repair my own appliances, or pull my own teeth...  

I went through the process of setting it up a few years ago and have contributed every year since, but haven't learned the ins & outs and don't understand the mechanics of how to fund the deal.

It would have taken an equal amount to recoup in time and legal fees so, sadly I moved on and went into development in construction at a time when the emphasis was not on having a degree, I came through the ranks and went far with talent.